U.S. patent number 4,378,234 [Application Number 06/266,572] was granted by the patent office on 1983-03-29 for particulate material collecting apparatus.
This patent grant is currently assigned to Kawasaki Jukogyo Kabushiki Kaisha. Invention is credited to Kiyoshi Aizawa, Mikio Murao, Takeshi Suzuki, Masaharu Takagishi.
United States Patent |
4,378,234 |
Suzuki , et al. |
March 29, 1983 |
Particulate material collecting apparatus
Abstract
A particulate material collecting apparatus including a
cylindrical member defining therein a spiral flow chamber for
forming a spiral flow of gas therein, an inlet duct and an outlet
duct connected to the cylindrical member tangentially to the inner
circumferential surface thereof, and a hollow inverted pyramidical
member secured to the lower portion of the cylindrical member. A
spiral flow guide plate having a convex surface curved radially
outwardly of the cylindrical member is interposed between the
cylindrical member and the inverted pyramidical member. The spiral
flow guide plate is positioned so as to define two openings, one
opening being located on the upstream side of the spiral flow of
gas and the other opening being located on the downstream side of
the spiral flow of gas. The spiral flow of gas is introduced from
the spiral flow chamber through the upstream side opening into a
material collecting space defined between an inner wall portion of
the inverted pyramidical member and a collected material guide
plate secured to the spiral flow guide plate to extend parallel to
the inner wall portion, so that particulate material incorporated
in the spiral flow of gas is separated by inertia from the gas and
collected in the inverted pyramidical member.
Inventors: |
Suzuki; Takeshi (Kobe,
JP), Murao; Mikio (Kobe, JP), Takagishi;
Masaharu (Kobe, JP), Aizawa; Kiyoshi (Kobe,
JP) |
Assignee: |
Kawasaki Jukogyo Kabushiki
Kaisha (Kobe, JP)
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Family
ID: |
27292043 |
Appl.
No.: |
06/266,572 |
Filed: |
May 22, 1981 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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97061 |
Nov 23, 1979 |
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Foreign Application Priority Data
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Dec 7, 1978 [JP] |
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53-152162 |
Apr 13, 1979 [JP] |
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54-44841 |
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Current U.S.
Class: |
55/338; 209/710;
209/722; 34/592; 55/397; 55/398; 55/399; 55/423; 55/427; 55/431;
55/457; 55/459.3; 55/460 |
Current CPC
Class: |
B01D
45/12 (20130101); B04C 7/00 (20130101); B04C
3/04 (20130101) |
Current International
Class: |
B01D
45/12 (20060101); B04C 3/04 (20060101); B04C
7/00 (20060101); B04C 3/00 (20060101); B01D
045/12 (); B01D 046/48 (); B04C 003/06 () |
Field of
Search: |
;55/397-399,423,426,459B,460,461,466,338,427,431-433,457,459R
;209/144 ;34/57E |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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686367 |
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Dec 1939 |
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DE2 |
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974442 |
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Dec 1960 |
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DE |
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120673 |
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Jan 1948 |
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SE |
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571222 |
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Aug 1945 |
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GB |
|
285480 |
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Jan 1971 |
|
SU |
|
430870 |
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Jun 1975 |
|
SU |
|
655406 |
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Apr 1979 |
|
SU |
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Primary Examiner: Lacey; David L.
Attorney, Agent or Firm: Jordan and Hamburg
Parent Case Text
REFERENCE TO RELATED APPLICATION
This is a continuation-in-part of application Ser. No. 97,061 filed
Nov. 23, 1979, now abandoned.
Claims
What is claimed is:
1. A particulate material collecting apparatus comprising:
a cylindrical member defining therein a spiral flow chamber having
a horizontal center axis, said spiral flow chamber having a
horizontal length of about 0.8-2.0 times the inner diameter of the
spiral flow chamber;
an inlet duct connected to one end of said cylindrical member
tangentially to the inner circumferential surface of the
cylindrical member;
an outlet duct connected to the other end of said cylindrical
member and having a cylindrical portion projecting into the spiral
flow chamber coaxially therewith, said cylindrical portion
projecting a length of about 0.1-0.2 times the inner diameter of
the spiral flow chamber and having a diameter of about 0.7-0.8
times the inner diameter of the spiral flow chamber;
a hollow inverted pyramidical member connected to the lower portion
of said cylindrical member including walls converging
downwardly;
a spiral flow guide plate located near the boundary between said
cylindrical member and said hollow inverted pyramidical member so
as to define two openings, said openings substantially extending
along the entire length of the cylindrical member parallel to the
horizontal center axis thereof, one of said openings being disposed
closer to the inlet duct than the other opening as measured along a
spiral line following the configuration of the spiral flow chamber
from the inlet duct to the outlet duct so that the openings are
respectively located at the upstream and downstream sides of spiral
flow of gas in said spiral flow chamber when the gas is first
introduced thereinto through the inlet duct; and
a collected material guide plate mounted in the hollow inverted
pyramidical member to define a material collecting space
communicating with said one opening located at the upstream side of
the spiral flow of gas.
2. A particulate material collecting apparatus as claimed in claim
1, wherein said outlet duct extends tangentially to the inner
circumferential surface of said cylindrical portion thereof.
3. A particulate material collecting apparatus as claimed in claim
1, wherein said spiral flow guide plate has a convex surface curved
radially outwardly of said cylindrical member.
4. A particulate material collecting apparatus as claimed in claim
3, wherein said spiral flow guide plate has the same curvature as
the inner circumferential surface of said cylindrical member.
5. A particulate material collecting apparatus as claimed in claim
3, wherein said spiral flow guide plate is arranged in an inclined
position oriented into the interior of the inverted pyramidical
member between the outer periphery of the spiral flow chamber and
the upper end of the inverted pyramidical member.
6. A particulate material collecting apparatus as claimed in claim
1, further comrpising at least one partition plate mounted in said
inverted pyramidical member perpendicularly to the center axis of
said cylindrical member, to divide the inverted pyramidical member
into a plurality of spaces.
7. A particulate material collecting apparatus as claimed in claim
1, wherein said collected material guide plate terminates at a
lower end spaced apart from the lower end of said inverted
pyramidical member.
8. A particulate material collecting apparatus as claimed in claim
1, further comprising a baffle plate projecting inwardly downwardly
from an inner wall portion of the inverted pyramidical member
toward said collected material guide plate located opposite the
baffle plate to further define said material collecting space.
9. A particulate material collecting apparatus as claimed in claim
1, wherein said cylindrical member includes an inclined surface
portion formed at the lower end portion of an end wall thereof at
which said inlet duct is connected to the cylindrical member, said
inclined surface portion being inclined inwardly downwardly and
connected to said inverted pyramidical member.
10. A particulate material collecting apparatus as claimed in claim
9, wherein said inclined surface portion formed at the lower end
portion of an end wall of said cylindrical member is planar in
shape.
11. A particulate material collecting apparatus as claimed in claim
9, wherein said inclined surface portion formed at the lower end
portion of an end wall of said cylindrical member is in the shape
of a convex surface curved outwardly.
12. A particulate material collecting apparatus as claimed in claim
1, wherein said cylindrical portion of said outlet duct includes an
inclined surface portion formed at a lower end portion of an end
wall of the cylindrical portion, said inclined surface portion
being inclined toward said cylindrical member so that the inclined
surface portion is disposed immediately below the outlet duct.
13. A particulate material collecting apparatus as claimed in claim
1, wherein a spiral guide in the form of protrusion is provided in
the interior of the spiral flow chamber for promoting the spiral
movement of the gas stream.
14. A particulate material collecting apparatus as claimed in claim
1, wherein a spiral guide in the form of a groove is provided in
the interior of the spiral flow chamber for promoting the spiral
movement of the gas stream.
15. A particulate material collecting apparatus as claimed in claim
1, further comprising movable closure plates provided in the
opening located closer to the inlet duct, said closure plates being
spaced apart from one another in the axial direction of the
cylindrical member and movable axially of the cylindrical
member.
16. A particulate material collecting apparatus as claimed in claim
1, further comprising material collecting means connected to a
lower end of said inverted pyramidical member to separate material
from the gas introduced into the inverted pyramidical member.
17. A particulate material collecting apparatus as claimed in claim
16, further comprising an induction blower located between and
communicating with said material collecting means and said
cylindrical member so as to cause the gas in the pyramidical member
to flow into the collecting means and to transfer the gas to said
cylindrical member from a side at which said inlet duct is
connected after the material is removed from the gas at the
material collecting means.
18. A particulate material collecting apparatus as claimed in claim
17, wherein said induction blower is connected to said cylindrical
chamber so that the material-free gas is introduced into said
cylindrical member tangentially to the inner circumferential
surface thereof.
19. A particulate material collecting apparatus as claimed in claim
16, further comprising an induction blower located between and
communicating with said material collecting means and said outlet
duct so as to cause the gas in the pyramidical member to flow into
the collecting means and to transfer the gas to the outlet duct
after the material is removed from the gas at said material
collecting means.
20. A particulate material collecting apparatus as claimed in claim
1, further comprising material collecting means connected to a
lower end of the material collecting space, and an induction blower
located between and communicating with said material collecting
means and said cylindrical member so as to cause the gas to flow
into the collecting means and to transfer the gas to said
cylindrical member from a side at which said inlet duct is
connected after material is removed from the gas at the material
collecting means.
Description
BACKGROUND OF THE INVENTION
This invention relates to a particulate material collecting
apparatus.
Cyclones have hitherto been most popular as particulate material
collecting apparatus. In cyclones, two types of vortical flows,
i.e. forced vortical flow and semi-free vortical flow are formed,
and the two types of vortical flows interfere with each other to
cause a loss in pressure. To minimize mutual interference of the
two types of vortical flows for reducing pressure loss requires an
increase in the size of the apparatus which entails an increase in
capital and operating cost.
SUMMARY OF THE INVENTION
This invention has as its object the provision of a particulate
material collecting apparatus capable of collecting particulate
material with a high degree of efficiency without an increase in
pressure loss in spite of its size being small.
The aforementioned object of the invention is accomplished by
providing a particulate material collecting apparatus comprising a
cylindrical member having a horizontal center axis, an inlet duct
and an outlet duct connected to the cylindrical member in a manner
to extend tangentially to the inner circumferential surface of the
cylindrical member, and a hollow inverted pyramidical member
secured to the lower portion of the outer circumferential surface
of the cylindrical member, the inverted pyramidical member having a
plurality of inner wall portions including a first inner wall
portion extending outwardly tangentially to the inner wall surface
of the cylindrical member. A spiral flow guide plate is mounted
between the cylindrical member and the inverted pyramidical member
and shaped as a convex surface extending radially outwardly of the
cylindrical member. The spiral flow guide plate is formed with two
openings, one opening located on the upstream side of a spiral flow
formed in the cylindrical member and the other opening located on
the downstream side thereof. A collected material guide plate
located in the inverted pyramidical member and connected to the
spiral flow guide plate extends parallel to the first inner wall
portion of the inverted pyramidical member to define a material
collecting space communicating with the cylindrical member through
the opening on the upstream side of the spiral flow. The
particulate material collecting apparatus according to the present
invention is high in the efficiency of collecting particulate
material, small in size and low in pressure loss.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic front view of the particulate material
collecting apparatus comprising one embodiment of the present
invention;
FIG. 2 is a side view of the apparatus as seen from left in FIG.
1;
FIG. 3 is a side view of the apparatus as seen from right in FIG.
1;
FIG. 4 is a sectional view taken along the line IV--IV in FIG.
1;
FIG. 5 is a schematic front view of the particulate material
collecting apparatus comprising another embodiment of the
invention;
FIG. 6 is a side view of the apparatus as seen from the right in
FIG. 5;
FIG. 7 is a schematic front view of the particulate material
collecting apparatus comprising still another embodiment of the
invention;
FIG. 8 is a side view of the apparatus as seen from the right in
FIG. 7;
FIG. 9 is a schematic sectional view of the particulate material
collecting apparatus comprising still another embodiment of the
invention;
FIG. 10 is a schematic front view of the particulate material
collecting apparatus comprising still another embodiment of the
invention;
FIG. 11 is a side view of the apparatus as seen from the right in
FIG. 10;
FIG. 12 is a side view of the particulate material collecting
apparatus comprising still another embodiment of the invention;
FIG. 13 is a schematic front view of the particulate material
collecting apparatus comprising still another embodiment of the
invention;
FIG. 14 is a schematic front view of the particulate material
collecting apparatus comprising still another embodiment of the
invention;
FIG. 15 is a schematic side view of the apparatus as seen from the
left in FIG. 14.
FIG. 16 is a schematic side view of the apparatus as seen from the
right in FIG. 14;
FIG. 17 is a schematic sectional view taken along the line
XVII--XVII in FIG. 14;
FIG. 18 is a schematic sectional view of the particulate material
collecting apparatus comprising still another embodiment of the
invention;
FIG. 19 is a schematic front view of the particulate material
collecting apparatus comprising a further embodiment of the
invention;
FIG. 20 is a schematic side view of the apparatus as seen from the
right in FIG. 19;
FIG. 21 is a sectional view of the particulate material collecting
apparatus comprising a further embodiment of the invention;
FIG. 22 is a schematic front view of the particulate material
collecting apparatus comprising a further embodiment of the
invention;
FIG. 23 is a schematic sectional view taken along the line
XXIII--XXIII in FIG. 22;
FIGS. 24, 25 and 26 are schematic front views of the particulate
material collecting apparatus each comprising another embodiment of
the invention;
FIGS. 27, 28 and 29 are schematic sectional views of the
particulate material collecting apparatus each comprising another
embodiment of the invention;
FIG. 30 is a schematic front view of the particulate material
collecting apparatus comprising a further embodiment of the
invention;
FIGS. 31A, 31B, 31C and 31D are schematic side views of the
particulate material collecting apparatus comprising further
embodiments of the invention;
FIG. 32 is a schematic front view of the particulate material
collecting apparatus comprising a further embodiment of the
invention;
FIG. 33 is a schematic side view of the particulate material
collecting apparatus comprising a further embodiment of the
invention;
FIG. 34 is a schematic front view of the particulate material
collecting apparatus comprising still another embodiment of the
invention;
FIG. 35 is a schematic side view of the particulate material
collecting apparatus comprising still another embodiment of the
invention;
FIG. 36 is a schematic front view of a cement material firing
system including a plurality of particulate material collecting
apparatus according to the invention arranged in a plurality of
stages;
FIG. 37 is a schematic side view of the system shown in FIG.
36;
FIGS. 38, 39, 40, 41 and 42 are graphs showing the results of
experiments conducted on the embodiment shown in FIGS. 14 to 17;
and
FIG. 43 is a schematic front view of the particulate material
collecting apparatus showing modification of the apparatus of FIG.
24.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preferred embodiments of the present invention will now be
described by referring to the drawings.
FIGS. 1 to 4 show one embodiment wherein an inlet duct 1 extending
vertically for introducing into the apparatus a gas stream having
incorporated therein particulate material to be collected is
connected to a cylindrical member 2 at one end thereof (right end
in FIG. 1) in a manner to extend tangentially to the inner
circumferential surface of the cylindrical member 2. The
cylindrical member 2 has a horizontal center axis and defines
therein a spiral flow chamber 3 circular in cross section. A
cylindrical portion 4 smaller in diameter than the cylindrical
member 2 is connected to the other end (left end in FIG. 1) of the
cylindrical member 2 substantially coaxially with each other and
has an outlet duct 5 connected thereto and directed upwardly
tangentially to the inner circumferential surface of the
cylindrical portion 4. The cylindrical member 2 is closed by end
walls 6 and 7 at its opposite ends.
The cylindrical member 2 has a hollow inverted pyramidical member 8
extending along the entire length of the cylindrical member 2,
which is connected to the lower portion of the outer
circumferential surface of the cylindrical member 2. The inverted
pyramidical member 8 has a first inner wall portion 8a extending
obliquely downwardly tangentially to the circumferential surface of
the spiral flow chamber 3, a second inner wall portion 8b disposed
in spaced juxtaposed relation to the first inner wall portion 8a
and extending obliquely downwardly tangentially to the
circumferential surface of the spiral flow chamber 3, the first and
second wall portions 8a and 8b nearing toward each other in going
downwardly, and a third inner wall portion 8c and a fourth inner
wall portion 8d disposed at right angles to the first and second
inner wall portions 8a and 8b and in spaced juxtaposed relation to
each other to extend obliquely downwardly toward each other. The
inverted pryamidical member 8 has a material collecting cylinder 9
connected to its lower end.
Located at the upper end of the inverted pyramidical member 8 and
extending along the entire length of the cylindrical member 2 in a
manner to substantially separate the spiral flow chamber 3 from the
inner space of the inverted pyramidical member 8 is a spiral flow
guide plate 10 which is curved with the same curvature as the wall
of the cylindrical member 2 and is disposed on or inside of the
circumferential surface of the cylindrical member 2. Openings 11
and 12 are formed between the spiral flow guide plate 10 and the
inner circumferential surface of the cylindrical member 2. When the
gas is introduced from the duct 1 into the cylindrical member 2 to
spirally flow therein, the opening 11 is located at an upstream
side and the opening 12 is located at a downstream side of the
spiral gas flow to communicate the spiral flow chamber 3 with the
interior of the inverted pyramidical member 8. The openings 11 and
12 both extend along the entire length of the cylindrical member
2.
Connected to the spiral flow guide plate 10 is a collected material
guide plate 13 extending in the inverted pyramidical member 8
parallel to the first inner wall portion 8a of the inverted
pyramidical member 8 to define a material collecting space 14 in
the inverted pyramidical member 8 communicating with the spiral
flow chamber 3 through the opening 11. The collected material guide
plate 13 terminates at its lower end 13a located in spaced
juxtaposed relation to the first inner wall portion 8a of the
inverted pyramidical member 8 and with a space l.sub.1 upwardly
away from the lower end of the inverted pyramidical member 8 as
shown in FIG. 4. The collected material guide plate 13 extends in
the inverted pyramidical member 8 parallel to the axis of the
cylindrical member 2 between the third and fourth inner wall
portions 8c and 8d. With this collected material guide plate 13 the
space 14 communicating with the opening 11 located on the upstream
side of the spiral flow and a space portion 16 communicating with
the opening 12 located on the downstream side of the spiral flow
are formed in the inverted pyramidical member 8.
In operation, a gas stream having incorporated therein particulate
material to be collected flows upwardly through the inlet duct 1
and is introduced into the spiral flow chamber 3 in the cylindrical
member 2 tangentially thereto. Since the spiral flow guide plate 10
is curved with substantially the same curvature as the wall of the
cylindrical member 2, the gas stream introduced into the spiral
flow chamber 3 flows spirally in the spiral flow chamber 3 without
being disturbed by the spiral flow guide plate 10. The gas stream
is discharged from the cylindrical portion 4 through the outlet
duct 5 after spirally flowing three times in the chamber 3. The
spiral movement of the gas stream causes the pressure near the
opening 12 at the downstream side of the spiral flow to be reduced
below the pressure near the opening 11 at the upstream side of the
spiral flow. As a result, a part of the gas stream spirally flowing
in the spiral flow chamber 3 is drawn by suction from the opening
11 to the opening 12 through the material collecting space portion
14 and the space portion 16.
When the gas stream flows spirally in the spiral flow chamber 3,
the particulate material incorporated in the gas stream is forced
by centrifugal forces to be displaced toward the inner wall surface
of the cylindrical member 2. Thus, the particulate material exists
in high concentration near the inner wall surface of the
cylindrical member 2. A gas stream containing the particulate
material in high concentration flows downwardly through the
material collecting space portion 14 along the inner wall portion
8a of the inverted pyramidical member 8 which extends outwardly
almost tangentially to the inner circumferential surface of the
cylindrical member and the collected material guide plate 13
disposed parallel to the inner wall portion 8a. Since the inverted
pyramidical member 8 is converging in going downwardly, the gas
stream having incorporated therein the particulate material of high
concentration has its speed of downward flow increased, so that the
particulate material drops by virtue of downwardly directed inertia
into the material collecting cylinder 9 with high efficiency, to be
eventually discharged from the apparatus. The gas stream flowing
downwardly through the material collecting space portion 14 changes
its direction of flow near the lower end 13a of the collected
material guide plate 13 and flows upwardly through the space
portion 16 in the inverted pyramidical member 8. Since the space
portion 16 is defined by walls diverging in going upwardly, the
speed of upward flow of the gas stream therein is reduced, thereby
increasing the efficiency with which the particulate material is
collected.
As shown in FIG. 4, the opening 11 has a width d1, which is made
relatively large when the particulate material incorporated in the
stream of gas introduced into the spiral flow chamber 3 has a
relatively high concentration and which is made relatively small
when it has a relatively low concentration. By this arrangement, it
is possible to reduce as much as possible the volume of the stream
of gas introduced into the material collecting space 14 to increase
the concentration of the particulate material in the stream of gas
introduced into the material collecting space 14, to thereby
increase the efficiency with which the particulate material is
collected in the inverted pyramidical member 8.
The cylindrical portion 4 has an end portion 4a projecting into the
spiral flow chamber 3, thereby preventing a gas stream containing
particulate material in high concentration from being drawn into
the cylindrical portion 4. The end portion 4a may be in conical
form converging widened or narrowed toward the end opposed to the
cylindrical member 2.
In the embodiment shown and described hereinabove, the particulate
material incorporated in the gas stream is forcedly led to the
material collecting space portion 14 to be separated from the gas
stream. This enables the particulate material collecting apparatus
according to the present invention to be reduced in size as
compared with cyclones of the prior art wherein particulate
material is separated from the gas stream by causing the
particulate material to move downwardly by gravity. Moreover, in
the particulate material collecting apparatus according to the
invention, no semi-free vortical motion is produced near the center
axis of the cylindrical member 2 as happens in the cyclones, so
that it is possible to reduce the inner diameter of the cylindrical
member 2. In the spiral flow chamber 3 in the cylindrical member 2,
the gas flows axially of the chamber while circling around the
center axis of the chamber. The absence of interference between two
types of vortical flows that happens in the cyclones minimizes a
power loss in the spiral flow chamber 3. The outlet duct 5 is
connected, through the cylindrical portion 4, to the cylindrical
member 2 tangentially to the spiral gas flow in the cylindrical
member 2, so that the gas can be smoothly discharged from the
spiral flow chamber 3 and the pressure loss can be further reduced.
In the outlet duct 5, the gas stream flows in a straight line
without spirally circling. Thus, when particulate material is
introduced into the outlet duct 5 to cause heat exchange to take
place between the particulate material and gas while they flow in
countercurrents (in the embodiments shown in FIGS. 36 and 37, for
example), the particulate material tends to be uniformly
distributed in the outlet duct 5, thereby increasing the efficiency
with which heat exchange is effected.
In the embodiment shown in FIGS. 1-4, the first inner wall portion
8a of the inverted pyramidical member 8 is disposed parallel to the
collected material guide plate 13 to increase the speed at which
the stream of gas flows downwardly in the material collecting space
14. If the speed of downward flow of the stream of gas is too high,
then the resistance offered to the downward flow of the gas will be
increased and difficulties will be experienced in introducing the
gas into the material collecting space 14, or the particulate
material will not drop into the material collecting cylinder 9 but
will disperse again in the upper portion of the space 16 as the gas
stream changes its direction of flow at the lower end 13a of the
collected material guide plate 13. To avoid these troubles, a gap
d2 (See FIG. 4) between the lower end 13a of the collected material
guide plate 13 and the first inner wall portion 8a may be increased
in size wider than the width d1 of the opening 11, to thereby
regulate the speed of downward flow of the gas stream.
In another embodiment, the length of the collected material guide
plate 13 may be reduced in such a manner that the space between the
lower end 13a of the plate 13 and the lower end portion of the
inverted pyramidical member 8 is greater than the space l.sub.1 of
the embodiment shown in FIGS. 1-4, so that the lower end 13a will
be located in the upper portion of the inverted pyramidical member
8. In addition, the invention is not limited to the center axis of
the cylindrical member 2 being horizontal, and the center axis
thereof may be inclined depending on the position in which the
apparatus is installed. The third inner wall portion 8c may be
arranged as indicated at 8c' and 8c" in dash-and-dot lines in FIG.
1.
Another embodiment of the invention is shown in a front view in
FIG. 5 and in a right side view in FIG. 6. In FIGS. 5 and 6, parts
similar to those shown in FIGS. 1 to 4 are designated by like
reference characters. The embodiment shown in FIGS. 5 and 6 is
essentially similar to the embodiment shown in FIGS. 1 to 4 and has
a material collecting means 40, such as a cyclone, connected to the
material collecting cylinder 9. Part of the gas flowing downwardly
through the material collecting space portion 14 is introduced by
an induction blower 41 into the material collecting means 40. This
reduces the amount of the particulate material in the gas returned
from the space portion 16 to the spiral flow chamber 3 through the
opening 12. The gas free from particulate material introduced into
the material collecting means 40 is blown by the induction blower
41 into the spiral flow chamber 3 through the end of the
cylindrical member 2 to which the inlet duct 1 is connected, to
flow axially of the cylindrical member 2 toward the cylindrical
portion 4. Introduction of the material-free gas into the spiral
flow chamber 3 has the effect of promoting the spiral flow of gas
containing a high concentration of particulate material in the
vicinity of the inner wall surface of the cylindrical member 2,
without disturbing the spiral flow of gas in the spiral flow
chamber 3. The material-free gas is introduced into the spiral flow
chamber 3 through the center of the end wall 6, pressure in the
center of the end wall 6 being lower than pressure in the opening
11, so that the induction blower 41 can be dispensed with when the
material collecting means 40 has a relatively low pressure
loss.
Still another embodiment is shown in a front view in FIG. 7 and in
a right side view in FIG. 8. Parts similar to those shown in FIGS.
1 to 4 are designated by like reference characters. In this
embodiment which is similar to the embodiment shown in FIGS. 5 and
6, it is to be noted that the material-free gas from the material
collecting means 40 is introduced into the spiral flow chamber 3 by
the induction blower 41 through a duct 1a connected to the chamber
3 tangentially to its inner circumferential surface in the vicinity
of the connection between the inlet duct 1 and the cylindrical
member 2. The provision of the duct 1a enables the speed of spiral
flow in the spiral flow chamber 3 to be increased. The port through
which the material-free gas is introduced into the spiral flow
chamber 3 has a lower pressure than the opening 11, so that the
induction blower 41 can be dispensed with when the material
collecting means 40 has a relatively low pressure loss.
FIG. 9 is a front view of still another embodiment wherein parts
similar to those shown in FIGS. 1-4 are designated by like
reference characters. What is noteworthy in this embodiment is that
clean gas from the material collecting means 40 is led to the
outlet duct 5. This embodiment may be lower in the efficiency with
which the particulate material is collected than the embodiments
shown in FIGS. 5 and 6 and FIGS. 7 and 8. However, since the gas
introduced into the cylindrical member 2 is reduced in volume, it
is possible to reduce the sizes of the cylindrical member 2,
inverted pyramidical member 8 and material collecting means 40 and
to reduce the capacity of the induction blower 41.
Still another embodiment is shown in a front view in FIG. 10 and a
right side view in FIG. 11. Parts similar to those shown in FIGS. 1
to 4 are designated by like reference characters. In this
embodiment, a material collecting means 47 is secured to the lower
portion of the cylindrical member 2, in order to separate the
material collecting space from the hollow inverted pyramidical
member 8. The material collecting means 47 includes a material
collecting duct 43 maintained in communication with the spiral flow
chamber 3 through an opening 42 and a hopper 45 maintained in
communication with an opening 46. The opening 46 is located
relative to the opening 42 on the downstream side of the spiral
flow of gas when the gas is introduced into the chamber 3 through
the duct 1. The material collecting duct 43 has an inner wall
portion 43a extending tangentially to the inner circumferential
surface of the cylindrical member 2 and is converging downwardly.
Connected to the lower end of the cylindrical member 2 adjacent to
the opening 42 and spaced from the material collecting duct 43 by a
spiral flow guide wall 44 is the hopper 45 which is disposed
adjacent the material collecting duct 43. The absence of the spiral
flow guide plate 10 between the spiral flow chamber 3 and the upper
end of the hopper 45 enables large masses of particulate material
to drop into the hopper 45 without any interference. The gas stream
introduced into the spiral flow chamber 3 is passed in spiral flow
along the inner wall surface of the cylindrical member 2 and the
spiral flow guide wall 44. The gas containing a high concentration
of particulate material in the vicinity of the inner wall surface
of the cylindrical member 2 is drawn by the induction blower 41
through the material collecting duct 43 into the material
collecting means 40. The gas drawn by the induction blower 41 may
be about 10% of the total gas led into the spiral flow chamber 3
through the inlet duct 1. The gas from which the particulate
material is removed is introduced into the cylindrical member 2
through the end thereof to which the inlet duct 1 is connected, to
flow axially of the cylindrical member 2 toward the cylindrical
portion 4.
FIG. 12 is a side view of still another embodiment, in which parts
similar to those shown in FIGS. 1 and 11 are designated by like
reference characters. In this embodiment, the gas drawn from the
spiral flow chamber 3 through the material collecting duct 43 and
having particulate material removed therefrom by the material
collecting means 40 is introduced into the spiral flow chamber 3 in
the vicinity of the connection between the inlet duct 1 and the
cylindrical member 2, tangentially to the spiral gas flow in the
chamber 3.
FIG. 13 is a front view of still another embodiment, wherein the
cylindrical portion 4 shown in FIGS. 1 to 12 is eliminated and an
outlet duct 66 is directly connected to an end of the cylindrical
member opposite to the end to which the inlet duct 1 is connected
and disposed coaxially with the cylindrical member 2. The outlet
duct 66 which is smaller in diameter than the cylindrical member 2
has an end portion 66a projecting into the spiral flow chamber
3.
FIGS. 14 to 17 show still another embodiment and parts therein
similar to those shown in FIGS. 1 to 13 are designated by like
reference characters. At a lower end of the end wall 6 of the
cylindrical member 2 a planar, inclined surface portion 6a inclined
inwardly downwardly is formed. The angle of inclination .alpha. of
the inclined end wall portion 6a with respect to the outer
circumferential surface of the cylindrical member 2 is set at a
value greater than the angle of repose or in the range between 45
and 55 degrees. The cylindrical portion 4 has a planar, inclined
surface portion 4b at the lower end opposite to the end at which
the cylindrical portion 4 is connected to the cylindrical member 2.
The planar, inclined surface portion 4b inclines inwardly
downwardly toward the cylindrical member 2 and has an angle of
inclination .beta. with respect to the outer circumferential
surface of the cylindrical member 2 like the planar, inclined
surface portion 6a.
The spiral flow guide plate 18 of this embodiment is shaped such
that it is located near the boundary between the inverted
pyramidical member 8 and the spiral flow chamber 3 to form the
opening 19 on the upstream side of the spiral flow in the chamber 3
and an opening 17 on the downstream side thereof which is large
enough to permit large masses of particulate material to drop
therethrough as shown in FIGS. 15 to 17. The spiral flow guide
plate 18 is curved to have the same curvature as the inner wall
surface of the cylindrical member 2 and extends along the entire
length of the cylindrical member 2.
In the inverted pyramidical member 8, the collected material guide
plate 20 which is shorter than the collected material guide plate
13 shown in FIGS. 1 to 4 is connected at its upper end to the end
of the spiral flow guide plate 18 which is near the opening 19 at
the upstream side of the spiral flow. The collected material guide
plate 20 is parallel to the inner wall portion 8a and extends
obliquely downwardly to define a space between the plate 20 and
inner wall portion 8a. The lower end 20a of the collected material
guide plate 20 is disposed above the lower end of the inverted
pyramidical member 8 in spaced apart relation. The spiral flow
guide plate 18 and the collected material guide plate 20 are
supported by a plurality of support plates 22 (three in number as
shown) spaced apart from one another axially of the cylindrical
member 2 and located at right angles to the center axis of the
cylindrical member 2.
The provision of the planar, inclined surface portion 6a in the end
wall 6 of the cylindrical member 2 prevents the particulate
material from accumulating on the lower end portion of the wall 6.
Thus an increase in pressure loss that might be caused by the
deposition of particulate material can be avoided, and a reduction
in material collecting efficiency that might be caused by the
dispersion of the accumulated particulate material can also be
avoided. As the planar, inclined surface portion 4b is provided in
the end wall of the cylindrical portion 4. The particulate material
introduced into the apparatus of the upper stage of a cement
material firing system as shown in FIGS. 36 and 37, in which the
particulate material collecting apparatus according to the
invention are mounted to form a suspension preheater, moves
downwardly through the outlet duct 5 and slides downwardly along
the inclined end wall portion 4b into the inverted pyramidical
member 8. Thus no accumulation of particulate material occurs in
the cylindrical portion 4 and consequently a pressure loss can be
avoided. As the spiral flow guide plate 18 has the opening 17 on
the downstream side of the spiral flow for permitting of passing
through of massive particulate materials, a large mass like a
coating is prevented from accumulation on the spiral flow guide
plate 18 and is moved easily downwardly into the inverted
pyramidical member 8. The collected material guide plate 20 may be
elongated downwardly as the material guide plate 13 shown in FIGS.
1-4.
FIG. 18 shows a modification of the embodiment shown in FIG. 17,
and parts shown therein similar to those shown in FIG. 17 are
designated by like reference characters. In this embodiment, the
spiral flow guide plate 18 and the collected material guide plate
20 of the embodiments described hereinabove are replaced by a
spiral flow and collected material guide plate 48 performing the
functions of the two plates 18 and 20. The spiral flow and
collected material guide plate 48 is located in a position
intermediate between the positions of the plates 18 and 20 shown in
FIGS. 14 and 17 and is curved radially outwardly of the spiral flow
chamber 3. The plate 48 is supported by the inner wall portion 8a
of the inverted pyramidical member 8 through support plates 49. The
use of the spiral flow and collected material guide plate 48
enables the same results as achieved by the spiral flow guide plate
and the collected material guide plate 20 shown in FIGS. 14 to
17.
FIG. 19 shows still another embodiment in a front view, and FIG. 20
shows this embodiment in a right side view. Parts similar to those
shown in FIGS. 1 to 18 are designated by like reference characters.
In this embodiment, the planar, inclined surface portion 6a of the
end wall 6 of the cylindrical member 2 may be replaced by an
inclined, convex-surface portion 6b which is curved outwardly. In
this case, the inclined surface 6b is inclined downwardly at an
angle of inclination .alpha.. Also, the planar, inclined surface
portion 4b of the cylindrical portion 4 may also be replaced by an
inclined, convex-surface portion 4c which is curved outwardly.
In still another embodiment, the inverted pyramidical member 8 may
be arranged along the entire length of the cylindrical member 2 and
connected to a vertical end wall of the cylindrical member.
Still another embodiment of the invention is shown in sectional
view in FIG. 21. In FIG. 21 parts similar to those shown in FIGS. 1
to 4 are designated by like reference characters. In this
embodiment a baffle plate 23 extending parallel to the axis of the
cylindrical member 2 between the third and fourth inner wall
portions 8c and 8d is secured to the second inner wall portion 8b
in a manner to project from the second inner wall portion 8b
obliquely downwardly into the space portion 16. The baffle plate 23
terminates at its lower end 23a disposed at higher level than the
lower end 13a of the collected material guide plate 13. With this
construction the particulate material remaining in the gas stream
which has failed to be separated from the gas stream by the
downwardly directed inertia of the downward gas flow in the
material collecting space portion 14 impinges on the baffle plate
23, so that the upward flow of the particulate material in the
space portion 16 is avoided, thereby increasing the efficiency with
which the particulate material is collected. At the same time, the
radius R of the gas stream changing its flow direction near the
lower end 13a of the collected material guide plate 13 is reduced
by the presence of the baffle plate 23. This increases the
centrifugal force acting on the particulate material in the gas
stream and promotes the drop of the particulate material.
FIG. 22 shows still another embodiment in a front view, and FIG. 23
is a sectional view taken along a line XXIII--XXIII in FIG. 22. In
FIGS. 22 and 23, parts similar to those shown in FIGS. 1-4 are
designated by like reference characters. As shown, a partition
plate 24 disposed perpendicular to the center axis of the
cylindrical member 2 is located between the first and second inner
wall portions 8a and 8b in the central position within the inverted
pyramidical member 8 disposed along the center axis of the
cylindrical member 2. The partition plate 24 divides the material
collecting space 14 defined by the first inner wall portion 8a and
the collected material guide plate 13 into two space portions 14a
and 14b. The space portions 16, which is defined by the collected
material guide plate 13, the second, third and fourth inner wall
portions 8b, 8c and 8d and the spiral flow guide plate 10, is
divided into two space portions 16a and 16b by the partition plate
24. By dividing the interior of the inverted pyramidical member 8
in the central position disposed along the center axis of the
cylindrical member 2 into two portions by the partition plate 24,
it is possible to return the gas introduced into the space portion
14a through a portion of the opening 11 disposed near the inlet
duct 1 into the spiral flow chamber 3 through the space portion 16a
and through a portion of the opening 12 disposed near the inlet
duct 1. It is also possible to return the gas introduced into the
space portion 14b through a portion of the opening 11 disposed near
the outlet duct 5 to the spiral flow chamber 3 through the space
portion 16b and through a portion of the opening 12 disposed near
the outlet duct 5. This is effective for prevention of
shortcircuiting of the stream of gas containing particulate
material in high concentration, which causes the gas to flow to the
outlet duct 5, so that the stream of gas can be made to positively
flow in spiral movement for a predetermined number of times or
three times as described hereinabove within the spiral flow chamber
3 and the efficiency with which the particulate material is
collected can be increased.
Both the baffle plate 23 and partition plate 24 may be provided in
the inverted pyramidical member 8. When this is the case,
synergistic effects can be achieved in increasing the efficiency
with which the particulate material is collected as described
hereinabove.
FIG. 24 shows still another embodiment wherein parts similar to
those shown in FIGS. 1-4 are designated by like reference
characters. In this embodiment, a spiral guide 25 in the form of a
protrusion is provided in the interior of the cylindrical member 2
and oriented in the direction of a spiral flow of the gas stream,
to thereby promote the spiral flow of the gas stream. The provision
of the spiral guide 25 has the particular effect of avoiding a
reduction in the force with which the gas stream flows in spiral
movement in the rear end portion of the spiral flow chamber 3.
Owing to the presence of the spiral guide 25, the particulate
material forced by centrifugal forces to move toward the inner wall
surface of the spiral flow chamber 3 can drop into the inverted
pyramidical member 8 along the spiral guide 25, thereby preventing
dispersion of the particulate material which might otherwise occur
again.
The spiral guide 25 formed as the protrusion may be replaced by a
spirally arranged groove 25' formed on the inner surface of the
spiral flow chamber 3, which is illustrated in FIG. 43. The spiral
guide 25 may be in the form of a discontinuous spiral instead of a
continuous spiral.
In another embodiment, a plurality of annular guide members 26 may
be provided as shown in FIG. 25 in the interior of the cylindrical
member 2 and secured to the inner wall surface thereof in a manner
to be located in spaced relation axially of the cylindrical member
2. This embodiment can achieve the same effects as the embodiment
shown in FIG. 24. The annular guide members 26 can serve
concurrently as the support plate 22 shown in FIG. 14.
FIG. 26 is a front view of still another embodiment wherein parts
similar to those shown in FIGS. 1-4 are designated by like
reference characters. In this embodiment, the cylindrical member 2
of the embodiment shown in FIGS. 1-4 is replaced by a conical
member 27 becoming smaller in diameter from the inlet duct 1 toward
the outlet duct 5. By this arrangement, the gas stream introduced
tangentially into the conical member 27 increases its force of
spiral movement toward the outlet duct 5 side of the conical member
27, thereby increasing the efficiency with which the particulate
material is collected.
FIG. 27 is a sectional view of still another embodiment wherein
parts similar to those shown in FIGS. 14-17 are designated by like
reference characters. This embodiment is similar to that shown in
FIGS. 14-17 except that the cylindrical member 2 is replaced by a
cylindrical member 28 which is constructed such that a downstream
portion 28a as seen in the direction of a spiral flow therein has a
larger radius of curvature R1 than the radius of curvature R2 of an
upstream portion 28b. By this constructional feature, the gas
stream introduced into the cylindrical member 28 flows spirally to
a satisfactory degree even if the spiral flow guide plate 18 is
relatively small in length, thereby avoiding collision of the gas
stream against the second inner wall portion 8b of the inverted
pyramidical member 8 and ensuring smooth spiral flow of the gas
stream. The "cylindrical member of a circular cross section"
includes the cylindrical member 28 of the aforesaid construction.
The spiral flow chamber 3 may be polygonal in cross section so long
as this cross sectional shape does not interfere with the spiral
flow of the gas stream.
FIG. 28 is a sectional view of still another embodiment wherein
parts similar to those shown in FIGS. 1-4 are designated by like
reference characters. In this embodiment, the spiral flow guide
plate 10 is formed with an opening 29, disposed immediately below
the center axis of the cylindrical member 2, which extends axially
of the cylindrical member 2 and allows communication between the
spiral flow chamber 3 and the space portion 16. The provision of
the opening 29 enables large masses of the particulate material
contained in the gas stream to move downwardly into the space
portion 16. A portion 10a of the spiral flow guide plate 10 is
interposed between the openings 11 and 29, so that the occurrence
of a turbulent flow in the spiral flow chamber 3 can be
minimized.
FIG. 29 is a sectional view of still another embodiment wherein
parts similar to those shown in FIGS. 14-17 are designated by like
reference characters. An opening 30 is formed on the downstream
side of the spiral flow guide plate 18 of the embodiment shown in
FIGS. 14-17 as viewed in the direction of the spiral flow, and a
second spiral flow guide plate 31 of the same radius of curvature
as the spiral flow guide plate 18 is provided. The opening 30 is
dimentioned such that large masses of the particulate material
contained in the gas stream can move downwardly therethrough into
the space portion 16.
FIG. 30 is a front view of still another embodiment wherein parts
similar to those shown in FIGS. 1-4 are designated by like
reference characters. When the inlet duct 1 is connected to the
cylindrical member 2 in such a manner that the side wall of the
inlet duct 1 is offset with respect to the side wall of the
cylindrical member 2, the particulate material in the gas stream
introduced into the cylindrical member tangentially to the
cylindrical member 2 through the inlet duct 1 is biased toward an
offset portion 32. Thus as the gas stream flows in spiral flow
toward the outlet duct 5, a high concentration portion of the
particulate material is formed spirally in the cylindrical member
2. To cope with this situation, movable closure plates 33 are
provided in the openings 11 on the upstream side of the spiral flow
of gas stream in such a manner that the closure plates 33 are
spaced apart from one another and movable axially of the
cylindrical member 2. By this structural feature, a small volume of
gas containing the particulate material in high concentration can
be led through the opening 11 into the material collecting space 14
if the closure plates 33 are fixed in place in a portion of the
cylindrical member 2 of low particulate material concentration.
This permits the particulate material to be collected with a high
degree of efficiency.
FIGS. 31(A), 31(B), 31(C) and 31(D) are side views of modifications
of the embodiment shown in FIG. 3. Parts in these figures similar
to those shown in FIGS. 1-4 are designated by like reference
characters. The inlet duct 1 of the embodiment shown in FIG. 3 may
be connected to the cylindrical member as shown in FIGS.
31(A)-31(C). Also, in place of the so-called linden type connection
described hereinabove, a connection may be adopted in which a side
wall portion 1a of the inlet duct 1 is in alignment with a line
tangent to the outer circumference of the cylindrical member 2. The
term "tangential direction" includes such connection.
FIG. 32 is a front view of still another embodiment wherein parts
similar to those shown in FIGS. 1-4 are designated by like
reference characters. In this embodiment, the inverted pyramidical
member 8 shown in FIGS. 1-4 is replaced by a member 34 in which the
material collecting cylinder 9 is displaced leftwardly in FIG. 32
to a position aligned vertically with the left end of the center
axis of the cylindrical member 2. Also, the inverted pyramidical
member 8 may be replaced by a member 35 shown in FIG. 33 in which
the material collecting cylinder 9 is displaced sideways to one
side of the cylindrical member 2 so that the member 35 is disposed
at right angles to the center axis of the cylindrical member 2.
Also, as shown in FIGS. 34, a plurality of inverted pyramidical
members 36 (two in number as shown) may be arranged axially of the
cylindrical member 2. This construction is preferable when the
number of spiral movements of the gas stream is increased by
increasing the length of the spiral flow chamber 3 and it is
desired to reduce the overall height of the apparatus.
FIG. 35 is a side view of still another embodiment in which parts
similar to those shown in FIGS. 1-4 are designated by like
reference characters. In this embodiment, the inverted pyramidical
member 8 of the embodiment shown in FIGS. 1-4 is replaced by a
member 37 secured to the lower end of the cylindrical member 2. The
member 37 includes inner wall portions 37a and 37b which are curved
outwardly. A collected material guide plate 38 also curved
outwardly is arranged to define an outwardly curved space 39
between the plate 38 and the outwardly curved inner wall portion
37a. By this structural feature, centrifugal forces act on the gas
stream introduced into the space 39 from the spiral flow chamber 3
through the opening 11, to bias the particulate material contained
in the gas stream toward the inner wall portion 37a. This reduces
the amount of particulate material entrained in an upwardly
directed gas stream flowing within the member 37 after changing its
direction at a lower end 38a of the collected material guide plate
38, thereby increasing the efficiency with which the particulate
material is collected.
FIG. 36 is a front view of a cement material firing system wherein
a plurality of particulate material collecting apparatus according
to the invention are incorporated in a plurality of stages, and
FIG. 37 is a side view thereof. Together with uppermost cyclones 53
and a lowermost cyclone 54, the particulate material collecting
apparatus 50, 51 and 52 constitute suspension preheaters. After
being supplied through a duct 55, particulate material is blown
from below by heated gas so that heat exchange takes place between
the particulate material and gas. As indicated by arrows, the
particulate material is then collected in the cyclones 53 and flows
downwardly into a duct 56. Repeating this process, the particulate
material moves through duct 56 particulate material collecting
apparatus 50, duct 57, particulate material collecting apparatus
51, duct 58, and particulate material collecting apparatus 52 to a
calcining furnace 59 where the particulate material is subjected to
decarbonation.
The particulate material calcined in the calcining furnace 59 is
led through a duct 60 to the cyclone 54 where it is collected and
sent to a rotary kiln 61. In the rotary kiln, the particulate
material is fired into clinker which is cooled in a clinker cooler
62 to be turned into an end product.
The path of flow of the heated gas is indicated by broken-line
arrows. The exhaust gas of high temperature from the rotary kiln 61
is introduced into the calcining furnace 59 together with secondary
air of elevated temperature for combustion extracted from the
clinker cooler 62 through duct 63. The heated gas from the
calcining furnace 59 is passed through the duct 60, cyclone 54,
duct 58, particulate material collecting apparatus 52, duct 57,
particulate material collecting apparatus 51, duct 56, particulate
material collecting apparatus 50, duct 55, and cyclones 53 and
subjected to heat exchange with the particulate material. After
effecting heat exchange, the gas is exhausted by an induction
blower 64.
The particulate material collecting apparatus 50, 51 and 52 are
smaller in size than cyclones of the prior art as described
hereinabove. Because of this, even if the apparatus are used to
constitute a suspension preheater in five stages (53, 50, 51, 52
and 54) as shown, the overall height is equal to a suspension
preheater consisting entirely of cyclones of the prior art arranged
in four stages. It goes without saying that heat exchange can be
effected with increased efficiency, and the power of the induction
blower 64 can be reduced because of reduced power loss of the
particulate material collecting apparatus 50, 51 and 52, when the
suspension preheater is arranged in five stages as compared with a
suspension preheater arranged in four stages.
By arranging another material collecting apparatus according to the
present invention, the material collecting apparatus 50, 51 and 52
and other one or more material collecting apparatuses constitute a
suspension preheater together with the uppermost stage cyclone 53
and the lowermost stage cyclone 54 in multiple stages. It goes
without saying that heat exchange can be effected with increased
efficiency, and can be constructed in overall height equal to a
suspension preheater consisting entirely of cyclones of the prior
art arranged in four stages.
FIGS. 38 and 39 show the results of experiments carried out on the
particulate material collecting apparatus shown in FIGS. 14 to 17.
In the figures, a solid line curve represents a result obtained
with the apparatus according to the present invention and a broken
line curve represents a result obtained with a cyclone of the prior
art used as a comparison. In FIG. 38, dash-and-dot line curves
show, for reference, results obtained with (A) an apparatus having
no inclined surface portion 6a in the lower end portion of an end
wall of the cylindrical member 2 and no spiral flow guide plate 18
and no collected material guide plate 20 and (B) an apparatus
having the inclined surface portion 6a but having no spiral flow
guide plate 18 and no collected material guide plate 20. In FIG.
38, it will be seen that the provision of the inclined surface
portion 6a in the end wall 6 of the cylindrical member 2 and the
provision of the spiral flow guide plate 18 and the collected
material guide plate 20 in the upper and middle portions
respectively of the inverted pyramidical member 8 has the effect of
increasing the material collecting efficiency of the particulate
material collecting apparatus according to the invertion to a level
almost equal to that of a cyclone of the prior art. Namely,
reference is especially made to the solid line curve showing the
apparatus of the present invention in FIGS. 14-17 and the curve (A)
showing the apparatus without the inclined surface portion, the
spiral flow guide plate and the collected material guide plate.
Since the apparatus of the present invention is provided with the
inclined surface portion 6a, the spiral flow guide plate 18 and the
material guide plate 20, the material collecting efficiency is
improved up to the level almost the same as that of the cyclone,
within 1%.
On the other hand, the pressure loss .DELTA.p of a particulate
material collecting apparatus can be generally expressed by the
following equation: ##EQU1## where .zeta.: coefficient of pressure
loss.
.gamma.: specific gravity of gas.
v: velocity at which gas is blown into the apparatus.
g: gravitational acceleration.
From equation (1), it will be seen that the larger the coefficient
of pressure loss .zeta., the greater is the pressure loss .DELTA.p
under the condition that the specific gravity of gas .gamma. and
the velocity at which gas is blown into the apparatus v are
maintained constant. FIG. 39 shows that the coefficient of pressure
loss .zeta. is markedly lower in the apparatus according to the
invention (a solid line) than a cyclone of the prior art (a broken
line). From this, it can be concluded that the pressure loss
.DELTA.p is lower in the apparatus according to the invention than
in a cyclone of the prior art.
Accordingly, when the collecting apparatus of the present invention
is used in the cement industry as shown in FIGS. 36 and 37, the
material collecting efficiency is almost the same as it would be
using prior art cyclones, but the pressure loss in operating the
system is less than half of that of the prior art cyclones.
Consequently, energy efficiency of the system is significantly
improved in total.
In practice, when the apparatus is used in the system as shown in
FIGS. 36 and 37, the mean diameter of the particles to be collected
is 50 .mu.m, including particles less than 10 .mu.m, for example,
cement material, alumina powder and the like, and the particle
suspension in the gas is at about 900.degree. C. and of a density
of 1.2-1.8 kg/Nm.sup.3. For the collection of particles from such a
suspension, it is preferable to make the apparatus of hereinafter
specified dimensions to further improve the collecting efficiency
and decrease the pressure loss.
FIGS. 40, 41 and 42 show relationships of both pressure loss
coefficiency and collecting efficiency to ratios of dimensions of
specific parts of the apparatus of the present invention.
In FIG. 40, the relation between the ratio of the length of the
spiral flow chamber to the inner diameter thereof and the
collecting efficiency and pressure loss coefficiency is disclosed,
in which when the ratio of the length to the inner diameter is
between 0.8-2.0, the pressure loss coefficiency is relatively low.
Namely, a mixture of the particulate with the gas is spirally
circulated around the horizontal axis of the spiral flow chamber to
smoothly and perfectly separate the particulate from the gas and is
exhausted through the outlet duct 5, wherein the gas drawn into the
spiral flow chamber is neither agitated nor mixed again with the
separated particulate. It is to be noted that if the value of the
ratio is small, the collecting efficiency becomes lower, and if the
value is large, the pressure loss increases with the length of the
chamber.
FIG. 42 shows the relation between the ratio of the inner diameter
of the end portion of the cylindrical portion 4 to that of the
spiral flow chamber 3 and the collecting efficiency and pressure
loss coefficiency, in which when the ratio is between 0.7-0.8, the
pressure loss coefficiency can be maintained relatively low. In the
present invention, the particulate in the gas can be almost
completely separated from the gas while passing through the spiral
flow chamber 3, so that a value in the above range can be selected.
If the ratio is below 0.7, the pressure loss coefficiency becomes
high, and if the ratio is above the range, the collecting
efficiency decreases.
In FIG. 41, there is shown the relation between the ratio of the
length of the portion 4 projecting into the spiral flow chamber 3
to the inner diameter of the spiral flow chamber 3 and the
collecting efficiency and pressure loss coefficiency. The ratio of
the projecting portion to the inner diameter is selected between
0.1-0.2. In case the ratio is higher than the above range, the gas
contains the particulate in high density due to insufficient
separation flow into the outlet duct to decrease the collecting
efficiency, and two kinds of vortexes are generated in the chamber
3 to thereby increase the pressure loss. On the contrary, in case
the ratio is lower than the aforementioned range, a part of the
particulate is exhausted together with the purified gas through the
outlet duct to thereby decrease the collecting efficiency.
From the foregoing description, it will be appreciated that
according to the present invention, there is provided a particulate
material collecting apparatus comprising a cylindrical member
defining therein a spiral flow chamber having a horizontal center
axis and circular or polygonal with the number of corners suitable
for not disturbing the spiral gas flow in cross section and means
for introducing gas tangentially to the spiral flow chamber to
permit a gas stream to flow in spiral flow in the spiral flow
chamber while passing axially of the chamber. By this arrangement,
interference of two types of vortical flows with each other
occurring in a cyclone can be avoided to thereby minimize a loss of
pressure. In the particulate material collecting apparatus
according to the invention, a hollow inverted pyramidical member is
connected to the lower portion of the cylindrical member to
separate particulate material from the gas stream, and the
particulate material contained in the gas stream is forcedly
introduced into the material collecting space formed in the
pyramidical member by the collected material guide plate defining
an opening located at the upstream side of the spiral flow. This
makes it possible to reduce the size of the particulate material
collecting apparatus as compared with a cyclone of the prior art
wherein particulate material is caused to drop freely by gravity.
The gas stream having contained therein the particulate material of
high concentration is introduced from the opening located at the
upstream side of the spiral flow into the material collecting space
in which the gas flow speed is increased downwardly, so that the
particulate material drops acceleratedly by virtue of downward
inertia into the material collecting cylinder and is collected with
a high degree of efficiency.
While the invention is described with reference to the specific
embodiments, it is to be noted that the description is illustrative
and the invention is limited only by the appended claims.
* * * * *